1. Field of the Invention
This invention generally relates to an image sensing module capable of compensating the deformation of the optical component and, more particularly, to an image sensing module capable of compensating the deformation of the optical component due to the variation of operation temperature.
2. Description of the Related Art
Image capturing technology is widely applied in various products such as optical touch systems, distance measuring systems or other optical applications capable of performing corresponding processes to acquired images.
Generally speaking, in addition to the image sensor, an image sensing module further includes at least one lens configured to guide external lights smoothly into a photosurface of the image sensor. However, an operation temperature of the image sensing module will change during operation due to system operation or environmental change. For example in an optical touch system, an operation temperature of the touch screen thereof will increase due to the operation of the backlight module thereof to cause an operation temperature of the image sensing module disposed on the screen surface to rise at the same time, such that optical components disposed inside the image sensing module will deform due to the temperature rise.
Please referring to FIG. 1, it shows a schematic diagram of an image sensing module influenced by the temperature variation. When an operation temperature of the image sensing module 100 changes, the optical component (not shown) of the image sensing module 100 deforms and causes the field of view (FOV) of the image sensor in the image sensing module 100 to change.
For example in FIG. 1, an FOV of the image sensing module 100 is shown as the large triangle F1 at 20° C. and shown as the small triangle F2 at 70° C. If an object O locates at a fixed position as shown in the figure at this moment, the image sensing module 100 can acquire a first image P1 at 20° C. containing an object image O1 and acquire a second image P2 at 70° C. containing an object image O2. As shown in FIG. 1, image positions of the object O in the first image P1 and the second image P2 acquired by the image sensing module 100 have a position deviation therebetween. Therefore, if the image sensing module 100 calculates an object coordinate according to the object images O1 and O2, different coordinates will be obtained at different operation temperatures.
Accordingly, the present invention provides an image sensing module that can eliminate or at least significantly reduce the deformation problem in the prior art caused by the temperature variation.